I'm having a problem.. when i typed orkut.com then a message box appeared message box was saying saying "Orkut is banned you fool. The administrators didnt did this. Guess who did. Muhahaha" . and then the browser window is closed. can anyone help me out.

See if this takes you to the log in screen.Have your friends been spending any time on that machine without you there ? ?i GOT the solution as follows.

1.Press CTRL+ALT+DEL and go to the processes tab
2.Look for svchost.exe under the image name. There will be many but look for the ones which have your username under the username
3.Press DEL to KILL these files. It will give you a warning, Press Yes
4.REPEAT for more svchost.exe files with your username and repeat. Do not kill svchost.exe with system, local service or network service!
5.Now open My Computer
6.In the address bar, type C:\heap41a and press ENTER. It is a hidden folder, and is not visible by default.
7.Delete all the files here
8.Now go to Start --> Run and type Regedit
9.Go to the menu Edit --> Find
10.Type "heap41a" here and press enter. You will get something like this "[winlogon] C:\heap41a\svchost.exe C:\heap(some number)\std.txt"
11.Select that and Press DEL. It will ask "Are you sure you wanna delete this value", click Yes
12.Now CLOSE the registry editor.
Now the virus is gone. But be sure to delete the autorun.inf file and any folder whose name ends with .exe in the pen drive.

UPDATE
It seems that they have named this malware as w32.USBWorm and according my friend, Avast is able to detect and remove it. I hope the other antivirus software will also be able to remove it soon.

I'm not sure i would trust this removal but i'm glad it worked for you...ya it worked and now no problem.